Measurement of eccentricity of hollow shafting



E. R. FEEHRER ET 'AL MEASUREMENT OF ECCENTRICITY OF HOLLOW SHAFTIN 3 Sheets- Sheet 1 July 12, 1938.

Filed April 15, 1956 E 12055". 1 66i??? WI/Z21 ffiizfilzari.

y 2, 1938. E. R. l -EEHRER ET AL 2,123,355

. MEASUREMENT OF ECCENTRICITY OF HOLLOW SHAFTING Filed April 15, 1936 3 Sheets-Sheet 2 l1 gwuantozd 1.3.2 125035 Fkifl i/@1127? amri.

July 12, 1938- E. R. FEEHRER ET AL 2,123,355

MEASUREMENT OF ECCENTRICIIY 0F HOLLOW SHAFTING Filed April 15, 1936 3 Sheets-Sheet 3 I gwuemtow I Y v I Eliassfkeflw K5 Wm lfl'mrt.

Patented July 12, 1938 wire a stares MEASUREMENT OF ECCENTRICITY OF HOLLOW SHAFTING Application April 15, 193e, Serial No. 74,434

13 Claims.

This-. inventionrrelates.to apparatus for measuring the bore of :hollow. shafting.

It is an. object of. this invention to provide meansfor determining the presence of and the 5. amount. of eccentricity in the bore of a hollow shaft atrany. point along the length thereof.

It is a further object to provide means for determiningnaccuratelythe locations of the several points alongthe length of 2 a. hollow shaft, at

'" which such measurements are taken.

The novel features of our invention will be more fully understoodfrom the following description and claims, taken with the drawings, in which Fig. 1 is aside elevation of our invention, partiall'y in section;

Fig. 2 1s asection along the line 2-2 of Fig. 1;

Fig. 3 is an enlarged fragmentary section along the line 3 -3 of Fig. 1;

Fig. 4 is an enlarg'edend-elevation of one of go-rthe anchor members forming apart of our invention;

Fig. 5 is a view in section along the line 55-of Fig. 4;

Fig; 6 is a fragmentary view in section along the Fig. '7 is an enlarged'view of a portion of the other anchor member; 7

Fig; 8 -is a longitudinal section of atapered-end shaft; and showing a modifiedform of ourinven- BO tion;

Fig. 9 is an enlarged View of the modified form of our invention shown'in Fig. 8;

Fig. 10 is an end elevation of the modified form of our invention shown in Fig. 9.

Referring-now to Fig. 1, the hollow shaft II is shownmounted' on-driven-rollerl2 and nondriven' rollersl'al Roller 12 is driven by motor I l. The places (notshown) on the shaft which rest on therollers are-so-called true spots go which are usedin-the machining operation for steady rest supports and for reference points in settingthe shaft; Four smooth and fairly heavy wires l5 are stretched through-the bore of shaft I I and are held in position relative to each other 45 by spacers It. At oneend wires l5 'areconnected to anchor member ll and at the other end to anchor member l8: passes through bracket 26, secured at the top of anchor member I1; and threadedly engages the 50 threaded portion 21 of bracket 23. By turning crank 28; blockfill and wires l5 may be raised or lowered in slot l9. Four threaded bolts 29 to which the ends of wires lt are'secuied, pass through block" and nuts 36.

Vertical threaded bolt The outer ends 55 i of bolts 29 which are rectangular: are mounted in plate 3! to prevent rotation of the bolts. Thus, by turning nuts 30, tension on each one of wires IEcan be individually adjusted.

Vertically slidable inslot 32 in anchor member. I8Jis housing 33which is held in the slot by flanged bracket 34. Bracket 34 is secured to guide-portion 35' of housing 33 by screws 39. Vertical threaded bolt 37 passes through bracket 33 secured at the top of anchor member IB and threadedly engages the threadedportion 39 of flanged bracket 36." By turning crank til, housing 33 and wires l5 may be raised or lowered in slot 32. Four threaded bolts M pass through and. engage threaded collars 42, the head portions 63 ofwhich are enclosed within housing 331 The outer ends of bolts 4| are also rectangular and are mounted in plate 44 to prevent theirlrotation. Mounted on :collars 52 and keyed thereto by keys 45 are spur gears 46'. Gear Mmounted on shaft 48 in housing 33 is turned by crank 49 and, through gear 5i); also mounted on housing 33; turns all four spur gears t? simultaneously. Through the interaction of these parts, the tension on all four: wires l5 may be adjusted in one movement, because threaded collars 52, keyed to spur gears 56, are causedto revolve and move bolts ll'inwardly or outwardly, as desired, to tighten or loosen wires i5.

Mounted on wires l5 and slidable thereon is carrier 5!, which supports dial micrometer gauge 52' and incandescent lamp 53. Pin 5 5, which protrudes vertically from the top of gauge 52, engages the innerwallof hollow shaft l l and actuates the pointer on the gauge. Lamp 53 is blackened at its outer end in order to eliminate glare in the eyes of the observer while still lighting the dial of the gauge. Electric cord 55 supplies current to lamp 53 and at the same time serves as a means for sliding carrier 5| along wires l5;

In the modified form of our device as shown in Figs. 8; 9 and 10, the. structure is the same as hereinbefore described, except as regards the carrier and gauge assembly. In this form the carrier comprises ring member 66 and circular plate 6!, both of which have grooves 62 adapted to receive wires l5. Side pieces 63 and bottom piece 64 which are riveted to ring member fill and plate 6| serve to join the two latter members and hold them in position relative to each other. Between ring member and plate 6! dial micrometer gauge 65 is mounted by means of lugs or pins 66 which engage bosses 67 on side pieces lit. Pin 68, when the gauge is in operative position, protrudes vertically from the gauge and engages the bore ofjhollow shaft 69 to actuate the pointer on the gauge. Spring 10 serves to hold gauge 65 in vertical position. Stop member I I, fastened to the back of gauge 65, engages shoulder 12, screwed to plate. 6|, to prevent rearward movement of gauge 65 beyond the vertical position. Measuring tape I3 may be used to slide the carrier along wires I5, and at the same time it shows the position of the carrier within the shaft. As shown in dotted lines in Figs. 8 and 9, when the carrier enters the mouth of tapered-end shaft 69, gauge 65 swings forward on lugs 66, to permit passage through the mouth of the shaft. As the bore of the shaft widens out, gauge 65 is returned to the vertical position by the tension exerted by spring I0. Incandescent lamp I4 which is supplied with current by means of cord I5 serves to illuminate the dial on gauge 65.

Having described the construction of the sev eral parts and their relative position with each other, we will now describe the operation of our invention.

The hollow shaft l I to be tested is laid on rollers I2 and I3. Wires I5 are threaded through the bore of shaft II from anchor I1 and are secured at the other end to anchor I8, and the tension on wires I5 adjusted by means of crank 49 and nuts 30. By means of cranks 28 and 40 wires I5 may then be adjusted vertically so that they are substantially parallel to the bore of shaft II although extreme'care in this respect is not necessary. After wires I5 have been adjusted they have no contact with shaft II.

Carrier 5I is then slid along wires I5 until gauge 52 is just inside the bore of shaft I I. Wires I5 are adjusted vertically at both ends so that the contact point of pin 54 just touches the uppermost part of the bore of shaft II. Shaft II is then rotated very slowly by means of motor I4 which drives roller I2.

If the bore of shaft II is exactly concentric with the true spots on the outside of the shaft, the reading of dial gauge 52 will not change as the shaft rotates. If, however, there is any eccentricity of the bore, the reading of dial gauge 52 will decrease or increase as the high or low sides of the bore come uppermost. The difference between the maximum and minimum readings of dial gauge 52 is the difference between the maximum and minimum wall thicknesses of shaft I I. These maximum and minimum wall thicknesses are usually 180 apart, and thus half the difference between them, as shown by dial gauge 52, is the eccentricity of the shaft under observation.

Gauge 52 can be slid along wires I5 to any point in the length of shaft II at which an observation of eccentricity may be desired, and with light 53 reflecting against the face of dial gauge 52, its readings can easily be ascertained by observation through telescope 16, shown in Fig. 1. By means of the measuring tape 13 shown in Fig. 8, the position along the length of shaft I I at which each observation of eccentricity is made, may be determined with considerable accuracy.

As shown in Fig. 2, the letters, A, B, C and D are painted on the end of shaft II and serve as reference marks for the use of the observer in locating the eccentricity circumferentially. At one end of the shaft II side A may be the thinnest portion, while at the middle or at the opposite end conditions may have changed so that the thinnest portion will be on side B.

lhe operation of the modified form of our invention shown in Figs. 8, 9 and 10 is the same as just described, except that dial gauge 65 is there so arranged as to permit it to swing forward, allowing passage through the tapered end of shaft 69, after which it swings back into operative position.

It should be noted that if there is any sag in the group of four wires, or if they are not exactly parallel to the bore, it will not affect the determination of the eccentricity at any point along the length of the shaft, as the eccentricity is determined entirely from the difference between the maximum and minimum readings of the dial gauge at each point of observation.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. An apparatus for measuring the bore of a hollow shaft comprising supporting means adapted to be positioned interiorly of the bore of a shaft, measuring and indicating means movably mounted on said supporting means, anchor means positioned externally of the shaft for holding said supporting means in operative position within the shaft, means for supporting the shaft and rotating means for changing the operative positions of said measuring and indicating means and said shaft relative to each other.

2. An apparatus for measuring the bore of a hollow shaft comprising a plurality of wires adapted to be threaded through the bore of a shaft, a micrometer gauge slidably mounted on said wires, a pin projecting from said gauge to engage the inner face of said shaft, means positioned externally of the shaft for holding said wires in operative position within the shaft, means for supporting the shaft, and rotating means for selectively changing the point on the inner face of the shaft which is engaged by said 3. An apparatus for measuring the bore of a hollow shaft comprising supporting means adapted to be positioned interiorly of the shaft, means external of the shaft for holding said supporting means in operative position relative to the bore of the shaft, measuring and indicating means mounted on said supporting means adapted to engage the inner face of the shaft and means for rotatably supporting the shaft.

4. An apparatus for measuring the bore of a hollow shaft comprising flexible supporting means, means for holding said flexible supporting means in operative position relative to the bore of the shaft, measuring and indicating means slidably mounted on said flexible supporting means and means for rotatably supporting the shaft.

5. An apparatus for measuring the bore of a hollow shaft comprising a plurality of horizontally disposed wires, a micrometer gauge mounted thereon, said micrometer gauge being adapted to be drawn along said wires throughout the full length of the shaft, anchor means positioned externally of the shaft for holding said wires in operative position within the shaft, and means to support the shaft.

6. An apparatus for measuring the bore of a hollow shaft comprising a plurality of horizontally disposed wires adapted to be disposed interiorly of the shaft and extending throughout the full length thereof, a micrometer gauge slidably mounted on said wires, anchor means for holding said wires in operative position within the shaft, and means to rotatably support the shaft.

'7. In an apparatus for measuring the bore of a hollow shaft the combination with a plurality of horizontally disposed wires adapted to be threaded through the bore of the shaft, of a gauge mounted on said wires having a projecting pin adapted to engage the inner face of the shaft, means positioned at each end of the shaft for holding said wires in operative position with the shaft, and means for rotatably supporting the shaft, said gauge while in operative, position'being adapted to indicate the movements of said pm.

8. An apparatus for measuring the bore of -a hollow shaft comprising flexible track means, a micrometer gauge slidably mounted on said track means, means positioned externally of the shaft for holding said track means in operative position Within the shaft, and means for rotatably supporting the shaft.

9. An apparatus for measuring the bore of a hollow shaft comprising flexible track means, measuring means mounted on said track means, means for supporting said flexible track means and means for mounting the shaft rotatably rela tive to said measuring means.

10. An apparatus for measuring the bore of a hollow shaft comprising flexible track means, measuring means slidably mounted on said track means, means for supporting and means for tensioning said flexible track means, and means for rotatably supporting the shaft.

11. An apparatus for measuring the bore of a vertically, and means for mounting the shaft rotatably relative to said gauge.

12. An apparatus for measuring the bore of a hollow shaft comprising means to rotatably support the shaft, track means extending through the shaft, means positioned at each end of the shaft for supporting the track means, and a micrometer gauge slidably mounted on said track means for engaging the inner face of the shaft.

13. An apparatus for measuring the bore of a hollow shaft having tapered portions, comprising flexible track means adapted to extend through the shaft, a carrier frame mounted on said flexible track means, a gauge swingably mounted in bosses on said carrier frame, means for holding said flexible track means in operative position within the shaft, and means for rotatably supporting said shaft, said gauge being adapted to swing out of operative position to permit its passage through said tapered portions.

WALTER G. KUHNERT. E. ROSS FEEHRER. 

